I have installed Exchange 2007 in a simple small enviornment. I have put all the rules on one server. Mail & OWA are working great, but POP3 is not working. I am not sure how to enable it. I can't find anything in the GUI in how to enable it. I am not that good at the Powershell. Any help will be appreciate it.

Haha , it seems you are having fun with POP3 just like every one else. I can offer you a fast resolution which is to switch to another mailing system and not have to worry to fix POP3 issue . Ok, not an option then below is the hints you will need to resolve this:

I get it that you are still using the MS Exchange 2007 RTM as you can't find POP3 in the GUI. Yes, you guessed it they have added it to the GUI just like a lot of the other features in SP1. If SP1 is an option, then all you have to do is install it and then enable it from the GUI and then Enable it for users who needed it. If SP1 is not an option then keep reading below:

How to Enable Pop3 for Exchange 2007 RTM:

Ok before we begin few notes that you have to keep in mind:
1- By default, POP3 service is disabled on Exchange 2007.
2- the Administrator account is explicitly blocked from POP3 for security reasons. That means even if it seems enabled or you try to enable it, it might not function well. So if you are testing pop3 don't use any administrator account.

Ok, all that have been said how to enable it read below:

1- Enable POP3 service & set it to automatic at power shell run the following:

The above command will give you a list of all your users and the status of pop3 functions of them being Enabled or disabled.

3- Ok, now you have the list of user you want to enable POP3 for them and know if their account is enabled or disabled for POP3. To enable POP3 for any account execute the following command at Power shell.
PS > Set-CASMailbox -Identity <username> -PopEnabled $true

4- Ok, if your POP3 setup is not ready for secure Login then after following all the above steps when you try to login to pop3 you will start getting multiple login screens and fail to login as Exchange 2007 set POP3 for secure login by default to confirm the type of login you have you can execute:

PS > Get-PopSettings

and then check the field "LoginType" If it say "Secure login" then you might want to change it to "cleartext" for it in order to work unless your environment is setup and ready for the Secure Login. The command to do this is as follow:
PS > Set-PopSettings -LoginType PlainTextLogin

OK, now you are done. All of your POP3 enabled users should be able to login. Please post back if you have any further difficulties.